Linux Host Enumeration (Authenticated Post-Exploitation)

Linux Host Enumeration On a pentest once you have compromised a Linux host there stands a good chance you will want to go through further ‘Linux Host Enumeration’ from an authenticated position. If you have gained an unprivileged user shell such as a web user you are most likely also going to want to escalate your privileges to root or a higher privileged account and gather as much info as possible. The first stages of this are situational awareness and information gathering based on what you have right in front of you, ie starting with host enumeration. Now whether you have grown up with a Windows or a Linux background, you will probably be more au fait with one or the other. I tend to find as with myself people tend to fall into one camp or the other, probably simple due to the exposure and experience you have had with one or the other in the past. And the need to practice with the other, not so au fait side, is essential. For me I was more exposed to windows boxes.

This post will hopefully guide you through some of what I have learned with host enumeration for Linux operating systems, in this instance Debian Ubuntu. Commands will vary from distro to distro, however, this will give you a taste. Of course please feel free to comment on this particular post with what I have missed and I will be sure to update the post.

Starting on a Ubuntu 14.04 machine as root we would be looking to run the following, (some may seem obvious) however; this isn’t meant to be an exhaustive list more of a top commands:

System Information:

uname -a
cat /etc/*-release
cat /proc/version
netstat -antp
netstat -anup
iptables -L
dpkg -l
apache2 -v
mysql –version
cat /etc/resolv.conf
cat /etc/network/interfaces

User Information:

cat /etc/passwd (you will need a privilege account for this one!)
cat /etc/sudoers
cat history

Sensitive Files:

cat /etc/passwd
cat /etc/group
cat /etc/shadow

Potential SSH information:

cat ~/.ssh/authorized_keys
cat ~/.ssh/
cat ~/.ssh/identity
cat ~/.ssh/
cat ~/.ssh/id_rsa
cat ~/.ssh/
cat ~/.ssh/id_dsa
cat /etc/ssh/ssh_config
cat /etc/ssh/sshd_config
cat /etc/ssh/
cat /etc/ssh/ssh_host_dsa_key
cat /etc/ssh/
cat /etc/ssh/ssh_host_rsa_key
cat /etc/ssh/
cat /etc/ssh/ssh_host_key



Conducting a PowerShell Port Scan – Post Exploitation

How to conduct a PowerShell Port Scan. Using PowerShell to conduct a simple port scan is very useful. If you have compromised a Windows server on a pentest and want to conduct a quick port scan you can use PowerShell. This might be to verify open ports on a neighboring system or to check egress filtering outbound to the internet using a public IP.

Using this simple one liner will produce a port scan of all ports 1-65536, the code snippet will also ask you for the IP address you want to port scan. Of course you can swap out the port range or simply substitute the ‘1..65536’ for something shorter like ’80, 445, 3389′ just like in the second example:

And in action this looks like the below:

PowerShell Port Scan

PowerShell Port Scan


Conducting a PowerShell Ping Sweep

In this post we will look to see how we can conduct a PowerShell Ping Sweep. So you are on a pentest engagment and have just owned a box and can see an alternative subnet or have just pivoted into a new subnet. You know want to know what else is in that new subnet but can’t access it from your attack machine. You will want to see what is alive and so a quick ping sweep of the subnet is in order to see how many targets are in the range. Why not use PowerShell. This is pretty straightforward, we can use the following syntax to perform a ping sweep of a /24 subnet:

This should look like this in action:

PowerShell Ping Sweep